Seafloor evidence of a subglacial sedimentary system off the northern Antarctic Peninsula

Swath-bathymetry data and high-resolution seismic reflection profiles allow us to portray a subglacial sedimentary system off the northern tip of the Antarctic Peninsula, in the Central Bransfield Basin, during the Last Glacial Maximum with unprecedented detail. Postglacial reworking and sedimentation are weak enough for the subglacial morphology of the Last Glacial Maximum to be preserved on the present seafloor. The studied sedimentary system extends 250 km, from ~1000 m above sea level to ~2000 m water depth. The data set supports a model for subglacial sedimentary systems that consists of: (1) an upper ice catchment or erosional zone on the innermost continental shelf, extending onshore; (2) a transitional erosional-depositional zone on the inner shelf with drumlinized seafloor; (3) a depositional outer shelf zone with mega-scale bundle glacial lineations; and (4) a debris apron on the continental slope and base of slope formed under floating ice shelves with debris delivery linked to grounding lines along the shelf break. Keywords: subglacial sedimentation model, continental margin, Antarctic Peninsula, swath bathymetry.